Filter or strainer



T. C. MAKINS FILTER OR STRAINER Filed Feb. 16, 1938 @y M www u.. 4. muwhllllwnuf Aug. 29, v1939.y

Patented Aug. 29, 1939 PATENT oFrics FILTER OR STRAIN ER,l

Thomas Cliord Makins, Lincoln, England, as-

signor to Ruston & Hornsby, Limited, Lincoln,

England Appuanon February 16, 193s, serial No. 190,866 In Great Britain January 7, 1937 4 Claims.

nate ones constituting the other group, cominunicates or communicate with the outlet end thereof, whilst adjacent longitudinal passages ,15 communicate with each other through a fine slitlike opening or a number of similar successive openings formed between the end of each dividing wall and the `inner periphery of said conduit or casing.

2O In known constructions of filter of the above type as applied to fuel atomisers or injectors, the longitudinal passages communicate directly at their outer ends with the fuel oil in the conduit or casing and it has been found that foreign bodies of a fibrous nature pass readily through the slitlike opening or openings between adjacent longitudinal passages when they are carried along with the fuel oil into the atomiser or injector and obstruct the fine delivery orifice or L,3,0 orifices thereof. Y

The object of the present invention is to improve the efficiency of filters of the above type whereby they will collect or retain foreign bodies of a fibrous nature that may be present in the liquid to be filtered.

According to the present invention, one longitudinal passage or alternate longitudinal passages constituting one group, formedy between the exterior of the plug shaped body and the inner periphery of the conduit or casing in which it is fitted, communicates or communicate through small or line transverse holes or perforations with an axial or longitudinal hole or passage provided at one end of said body, whilst the other Y Vlongitudinal passage or the alternate longitudinal passages constituting the other group, communicates or communicate also through small or line transverse holes or perforations or through a port or ports of any other desired form with an axial or longitudinal hole or passage provided at the opposite end of said body.

Referring now to the accompanying drawing:

Figure l is a sectional elevation of a fuel in- 55 jector or atomiser showing the improved filter- YFir-.jure 3.

ing member in outside elevation applied to the inlet to the body or casing.

Figure 2 is a sectional elevation of the filtering member taken through the upper series of the small or fine transverse filtering holes therein, whilst Figure 3 is a sectional plan View of the filtering member taken on the line 3-3 of Figure 2.

In carrying out' the present invention as illustrated, the cylindrical bore l of the fuel inlet connection 2 of the fuel oil atomiser is iitted with a plug shaped filter body l2. The plug shaped lter body l2 is formed preferably from a solid rod which is machined so that cylindrical portions 4, 41 at each end fit closely within the l5 bore l of said inlet connection 2. Between these cylindrical end guide surfaces 4, 41 the rod is ground or machined to a slightly smaller diameter either throughout the distance between the end bearing portions or so as to provide inter- 20 mediate guide portions 42 preferably of narrow width' or depth as shown. Throughout substantially the whole of the distance between the cylindrical end portions 4 and 41, the periphery of the rod is formed with preferably four ats 5, 5 and 51, 51, the adjacent ones of which are at right angles to each other (see Figure 3) and are connected by a narrow strip 6 of the cylindrical surface of the rod. In cross section through the flats, the rod is therefore square l with the corners chamfered as clearly shown in Holes 1, 11 are bored axially into the rod from both ends to a suitable distance inwardly beyond the innerends of the cylindrical end guiding portions 4, 41. Towards the inlet end of i the pair of opposite iiats y5, 5, a series of fine holes 8, for example three, which may besituated in an axial plane, is bored transversely through the rod so that these holes pierce the axial hole 1 as Well as the surfaces of both flats '40 5, 5. A similar series of fine holes 81 is bored towards the other end of the other pair of opposite flats 51, 51 and these holes pierce the axial hole 'I1 at the opposite or outlet end of the rod as well as the surfaces of both of the latter flats.

When the pluglike filter body formed from a solid rod in the manner described above, is inserted in the fuel inlet connection Z, the space or spaces between the end of the partitionV wall at 6 separating adjacent longitudinal passages 50 9 and 91 thus formed at the exterior of the body, and the bore l of the inlet connection, provide a very minute slitlike opening or openings I0 (shown exaggerated in Figure 1 for clearness of illustration) so that solid particles that may be present in the fuel oil, and which would be liable to obstruct the delivery opening or openings l I of the fuel atomiser or injector, are prevented from passing through the several slitlike openings of the filter to the outlet.

With the foregoing construction, it will be understood that the fuel oil, which is under a high pressure, first passes into the axial inlet hole 'l in the plug shaped body, then through a series of small holes 8 connecting it with the corresponding passages 9 formed at the exterior of the plug between two opposite flats 5 and the bore l of the inlet connection 2 and from thence through the fine longitudinal slitlike opening or openings l between the turned down portion or portions of the end of each dividing wall at 6 and the bore I of the fuel inlet connection 2, into the other two opposite longitudinal passages 91, 91 at the exterior of the body, then through the series of small holes 81 connecting these passages with the axial fuel outlet 11 in the body.

It will be clear from the foregoing description that during the passage of the fuel through the filter body, any small foreign bodies of a fibrous nature that may be contained in the f uel oil will be obstructed by the Vsmall or iine holes 8 at the inlet end of the filter plug from entering the passages 9 between the exterior of the latter and the bore l of the inlet connection so that a more efficient filtration of the fuel oil will be effected than with known filters of the type to which the present invention relates.

Although in the foregoing construction a series of small or fine transverse holes is drilled towards both ends of the lter body between opposite flats Vthereon to pierce the respective axial holes drilled into the ends thereof, these transverse holes may be provided towards one end only of the body, preferably that which is to serve as the inlet end, so that at the opposite end the'` necessary communication may be effected otherwise as through a comparatively large hole or slot. In both of the above described constructions either end of the body may serve as the inlet end. To facilitate manufacture however, I prefer to use the construction first above described in which said small or fine transverse holes are provided at both ends of the filter body.

Although in the foregoing description, I have described a construction in which the flats on the body of the filter are connected one with another through a wall the end of which i's of a denite thickness as shown in Figures l and 3, I may modify that construction so that adjacent flats meet in an edge. Furthermore, I may arrange more than four flats on the filter body with the two groups of alternate longitudi nal passages formed between the iiats and the bore of the conduit or casing, communicating with their respective axial holes as lin the examples given above. The latter construction of filter would be more suitable for dealing with larger` quantities of liquid. Again, instead of flats I may provide grooves in the exterior of the filter body to form channels and the end of the connecting wall between adjacent channels may be of a definite thickness or the sides may meet in an edge at' the end of the wall.

In the accompanying drawing I have shown the present invention applied to a particular construction of atomiser, but it is to be understood that such construction is given by way of example as the present invention is applicable to any type or construction of fuel injector or atomiser.

What I claim is:

l. A liquid filter device comprising in combination a casing having a boring therein and a plug fitted into such boring, the plug having fluid passage means therethrough including a substantially axially extending passageway at one end and external cut-away portions extending longitudinally of the plug, the partition walls between said cut-away portions having ground off edges to provide relatively narrow filter openings connecting adjacent cut-away portions, at least one small transverse filtering aperture extending from said passageway to alternate cutaway portions of the plug, and a passageway at the other end of the plug in communication with alternate cut-away portions.

2. A liquid filter device comprising in combination a casing having a boring therein and a plug tted into such boring, the plug having a substantially axially extending passageway at one end and external cut-away portions extending longitudinally of the plug, alternate portions terminating intermediate the ends of the plug, the partition walls between said cut-away portions having ground oii edges to provide relatively narrow Iilter openings connecting adjacent cut-away portions, at least one small transverse filtering aperture extending from said passageway to alternate cut-away portions of the plug, and a passageway at the other end of the plug in communication with alternate cut-away portions.

3. A liquid lter device comprising in com- .bination a casing having a boring therein and a plug iitted into such boring, said plug having a portion at one end snugly tting such boring, said plug having a substantially axially disposed passageway extending from said end inwardly past said portion, external cut-away portions extending longitudinally of the plug from said l'st portion, the partition walls between said cutaway portions having ground off edges to provide relatively narrow iilter openings connecting adjacent cut-away portions, at least one small transverse filtering aperture extending from said passageway to alternate cut-away portions of the plug, and a passageway at the other end of the plug in communication with alternate cutaway portions.

4. A liquid filter device comprising in com- Vbinationa casing having a boring therein and a plug in such boring, said plug at each end having a substantially axially extending passage,

said plug having portions adjacent opposite endsV snugly iitt'ed in said boring, the cut-away portions extending longitudinally of the plug, alternate cut-away portions terminating at the first mentioned portions, the partition walls between said cut-away portions having ground oif edges to provide relatively narrow filter openings connecting adjacent cut-away portions, at least one small transverse filtering aperture extending from one of said passageways to alternate cutaway portions of the plug and at least one small transverse iiltering'aperture extending from the other of said passageways to the remaining cutaway portions.

THOMAS CLIFFORD MAKINS. 

